I want to make some prototypes but I am still torn apart on what to go for. Just brainstorming for ideas on Monday with our company. I am in some sort of a block here. What do you think are cost effective when making prototypes? Is it CNCs or 3D printers are cost effective?

That is a quite a tricky question, OP. I think it depends a lot on the geometry of the part and the kind of part you require. I would put it this way, no one process is cheap or more expensive, it simply depends on the kind of project you are working on. Care to elaborate on what you really want?

I agree with you man. I have been a CNC machinist for two months now and I think I can contribute something sensible to this forum. I have noticed that CNC machines doesn’t work on undercuts very well therefore they cannot produce quality geometries that 3D printers can. Moreover, CNC machines are subtractive thus wasting material with certain shapes. However in some cases, CNC provide for higher tolerance, smoother surfaces and stronger parts.

Now - this is what I mean. When dealing with metals parts, CNC are better and cheaper than 3D printers. Flat surfaces works better with CNC while sharp edges on the other hand tend to work better when 3D printed. More so, large things are expensive if you are using 3D printers therefore for it is less costly when using 3D printers on tiny parts, intricate parts and also detailed parts.

The bottom line is there are many CNC and 3D printing materials, therefore it is important to factor in the type of material when determining the cost effective method.

The OP has not specified what they want - so it is safe to make some assumptions. I think the cost isn’t usually the driver here. My point is, you can find a cheap CNC aluminum part from First Cut for as much price or even a little more expensive as you might pay for a SLA. So I will approach you question by giving reason why you should machine and not 3D print, and still hope to answer your question.

First, mostly 3D printing is not a production material therefore if you have a part in the material you will end up in using production with. Moreover, even if you can 3D print in your material you will still go to production with.

Finally, the reason why you should consider machining other than 3D printing is that, it allows tighter tolerance. Come to think of it, it is easier to take a few machining passes at a part until you get to plus or minus .001 which may prove to be difficult with 3D printers to carry out the same task. However, if you are looking for tight 3D printed parts, I would recommend that you try other prototypes other than Fineline Prototyping.

Personally, I think CNC machines are more realistic in terms of price, size and material. CNC routers can cut items as large as a house as tiny as jewelry. So basically, CNC machines are cost effective.

I am not sure whether this point answers any bit of your question but let me put it down though.I also think CNC machining is better since it offers a wide range of secondary operations including; assembly, insert and helicoils, polishing, plating, painting and powder coating. I doubt whether 3D printers has the same.